Historically, if an aircraft suffers a total loss of navigation, the aircraft may have to rely upon a navigation solution which was computed on the ground and uploaded to the aircraft in order to determine its position. Similarly, a pilot may have to use pilotage techniques to manually calculate the position of the aircraft using on-board maps and visual sighting of landmarks on the ground. Other methods of position determination when there has been a total loss of navigation may include calculations relying upon a fixed coordinate frame of known distances between ground based objects (such as ground stations or air traffic control) to calculate the position of the aircraft, or other legacy methods of position determination and navigation.
In addition, when an aircraft suffers a total loss of navigation, the aircraft may be incapable of determining and reporting its ownship position. As a result, the aircraft position information may not be available to other aircraft or to air traffic control which is not equipped with or loses surveillance radar coverage. This may require air traffic controllers to rely on legacy methods for tracking the airplane. Air traffic control may also be required to re-route other aircraft in order to avoid traffic conflicts. In addition, without knowing its position, an aircraft is not allowed to participate in Automatic Dependent Surveillance Broadcast (ADS-B) applications.
Therefore, there exists a need for improved methods and systems for backup navigation position determination of an aircraft.